The words literal, littoral sound the same but have different meanings and spellings. Why do literal, littoral sound the same even though they are completely different words?
The answer is simple: literal, littoral are homophones of the English language.
Being in accordance with, conforming to, or upholding the exact or primary meaning of a word or words.
Word for word; verbatim: a literal translation.
Avoiding exaggeration, metaphor, or embellishment; factual; prosaic: a literal description; a literal mind.
Consisting of, using, or expressed by letters: literal notation.
Of or on a shore, especially a seashore: a littoral property; the littoral biogeographic zone.
A coastal region; a shore.
The region or zone between the limits of high and low tides.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.
If they are spelled the same then they are also homographs (and homonyms); if they are spelled differently then they are also heterographs (literally "different writing").